|Publication number||US4897274 A|
|Application number||US 07/072,497|
|Publication date||Jan 30, 1990|
|Filing date||Jul 13, 1987|
|Priority date||Oct 29, 1986|
|Also published as||CA1294205C, DE3680916D1, EP0265544A1, EP0265544B1|
|Publication number||07072497, 072497, US 4897274 A, US 4897274A, US-A-4897274, US4897274 A, US4897274A|
|Inventors||Giovanni Candida, Luigi Perazzo|
|Original Assignee||W. R. Grace & Co.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (11), Referenced by (61), Classifications (25), Legal Events (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates to a highly water and gas permeable packaging multi-layer film, in particular a film for cheese packaging.
In the manufacturing of some types of cheeses, in particular molded rind soft cheeses, like for example Camembert, the cheese has to ungergo curing and surface moulds growth finishing processes, which are rather lengthy processes. Therefore such finishing processes are left to go to completion after the manufacturing and packaging of the cheese during its storage period before marketing.
During curing and surface mould growth the cheese absorbs oxygen from the environment and develops moisture and gases, in particular carbon dioxide. The material in which the cheese is packed has to possess therefore a certain permeability to such moisture and gases in order to permit a controlled absorption and removal thereof whereby a desirable finishing process of the cheese can take place.
The packaging materials used up to now for complying with the above mentioned requirements were mostly nontransparent laminates of oiled paper with various additional layers like, paper, aluminium paper, polypropylene, cellophane, etc. Their requested permeability was provided for by the fact that such packing materials were just loosely folded around the cheese by so permitting the moisture and gases to escape through the free spaces between the folds. Alternatively the prior art conventional packing materials were provided with small holes so creating a porosity allowing the package to "breathe".
Such prior art packaging laminates had drawbacks either because they did not guarantee a controlled moisture and gas exchange, or because due to their mostly non-transparent character they were subject to package tampering by users trying to check their contents, and this particularly in supermarkets.
It is an object of the present invention to provide a new type highly permeable packaging film particularly suitable for packaging moulded rind cheese.
It is a further object of this invention to provide a packaging film of the type mentioned above which enables an improved curing and mould growth finishing process for the cheese resulting in an extended shelf life of the same.
Still a further object of this invention is to provide a highly permeable packaging film, particularly for moulded rind cheese, which is transparent and heat sealable and therefore tamperproof.
It has been found that the above mentioned objects are achieved by a multi-layer highly permeable packaging film characterized in that it comprises at least one highly moisture and gas permeable core layer of a butadiene-styrene copolymer with a styrene content of from 60% to 80% by weight of the copolymer, and at least two outer layers having heat sealable and gas permeability properties.
The butadiene-styrene (BDS) copolymer core layer of the laminate film according to this invention confers to it high water vapour permeability values ranging advantageously from 100 to 400 g/m2.day, as measured by the ASTM E-96-66 or F-372-73 methods. Permeability values substantially higher than the above indicated higher limit are disadvantageous in that they can result in a too much dried cheese of poor quality. On the other hand, permeability values below the indicated lower limit are disadvantageous in that they can result in undesired bacteria and yeasts growth on the cheese surface.
Moreover the BDS core layer gives a high stiffness to the packaging film as required in order to guarantee machinability and sufficient resistance of the package during manipulation and transportation.
For illustrative purposes, a BDS copolymer could be used which is available from Phillips Petroleum Co. (USA) as KR-O5 Resin, having a melt flow index (MFI) of 0.5 to 10.
Preferably the thickness of the BDS core layer in the laminate according to this invention ranges from 5 to 30 micrometers.
The outer or "skin" layers of the laminate of this invention has the main function of enabling the laminate to be sealed, while not subtracting from the permeability of the whole laminate. Accordingly also such skin layers have to be made of a material having a certain gas permeability. Accordingly, while polyethylene or polypropylene does not comply with this permeability requirement, the outer layers can be selected from high permeability and sealable polyolefins like polybutylene and higher polyolefins. However preferred outer sealing layers are ethylene-vinylacetate (EVA) copolymers with a vinylacetate content of 8 to 28% by weight of the EVA and a MFI of 0.5 to 7, and the ethylene copolymers known as Very Low Density Linear Polyethylenes (VLDPE) as described in Plastics Technology, September 1984, page 113 and October 1984, page 13 as well as in a company brochure published in February 1984 by DSM in the Netherlands entitled "Stamilex PE". About 10 to 20% by weight of such VLDPE comprises an olefin comonomer, preferably chosen from C4--, C6-- and CB-alpha-n-olefins which have a MFI of 0.5 to 8.0.
In addition to the above cited preferred outer layers, these can be also selected from polybutylene and copolymers thereof, poly-4-methyl-pentene-1, polyethylene terephthalate glycol (PETG), polyether polyurethans and elastomeric copolyesters such as ECDEL 9967 sold by Eastman Kodak Co.
Among the above mentioned sealing layers, those indicated as preferred ones also contribute to, or at least do not impair, the high water vapour and gas permeability of the core layer, while also providing, especially in the case of VLDPE, a desirable abuse resistance (resistance to puncture, tear, etc.) property.
The laminate according to the invention can comprise more than the said three critical layers. For example it can comprise up to five layers, i.e. it can comprise one or two further intermediate layers which can be made of the same copolymers forming the skin or outer layers, or alternatively of other still moisture permeable polymers like adhesive resins, for example the modified EVA resin sold by DuPont under the trade name Bynel, or ionomeric resins such as the modified ethylene-methacrylic acid sold by DuPont under the trade name Surlyn.
Usually the laminates according to this invention are prepared with a total thickness ranging from 10 to 50 micrometers.
The laminate structure of the present invention can be manufactured by hot blown coextrusion process from a multilayer circular die, or by water quenching coextrusion and orientation which can possibly also render the laminate heat-shrinkable for particular uses thereof requiring such property. The skin layers may be added with a masterbatch containing antiblock and slip agents, or other conventional manufacturing or handling aids.
The laminate structure according to this invention is used by wrapping it around the food article, in particular a moulded rind cheese and by closing the package by sealing the laminate film. This latter can be trim, heat or bunch sealed. The stiffness of the film conferred to it by the BDS core layer enables its use on automatic packaging machines.
The following tables summarize some illustrative, but not at all limitative, embodiments of the laminate film of this invention and and report the respective moisture vapor transmission (MVT) properties and the oxygen and carbon dioxide properties thereof. The MVT or has been measured according to the ASTM methods E-96-66 or F-372-73, while the 02 and C02 permeabilities have been measured according to ASTM D-3985-81 and D-143-75, respectively.
TABLE I__________________________________________________________________________ MVT (g/m2.day at 38° C.Laminate film and 100% RH)__________________________________________________________________________ EVA 14% VA/ BDS /EVA 14% VA 170 MFI 5 MFI 6 MFI 5 5 u20 u5 u VLDPE 20% Octene/ BDS /VLDPE 20% Octene 105 MFI 6 MFI 6 MFI 6 5 u20 u5 u EVA 14% VA / Bynel CXA-E-162* / BDS /Bynel CXA-E-162*/EVA 14% 120 MFI 5 MFI 0.8 MFI 6 MFI 0.8 MFI 5 3 u3 u20 u3 u3 u VLDPE 20% Octene /EVA 28% VA / BDS / EVA 28% VA /VLDPE 20% 150ene MFI 6 MFI 7 MFI 6 MFI 7 MFI 7 3 u3 u20 u3 u3 u__________________________________________________________________________ *Trade mark of a modified EVA adhesive coploymer sold by DuPont
TABLE II______________________________________EVALUATIONS EVA/BDS/EVA (*)______________________________________MVT 170at 38° C., 100% RH(g/m2, 24 hrs)O2 PERMEABILITY 3,800at 23° C., 0% RH(cc/24 hrs, m2, bar)CO2 PERMEABILITY 21,000at 23° C., 0% RH(g/24 hrs, m2, bar)MODULUS, kg/cm2 9,000(ASTM D-882-75)______________________________________ (*) The film is that under point 1 of Table I.
From the above description and examples of the laminate film of this invention it appears that it is a novel type packaging film combining transparency, sealability properties, high moisture and gas permeability properties and high stiffness characteristics. The permeability shown even in a sealed condition guarantees a tamperproof food packaging which is a very desirable characteristic from a hygienic point of view. The intrinsic permeability of a controlled magnitude ensured by the nature of the materials comprised in the laminate according to this invention enables an improved curing and proper surface moulds growth, resulting in extended shelf life of a respective food package.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2266700 *||Dec 2, 1939||Dec 16, 1941||Cheese package|
|US2961322 *||Feb 1, 1957||Nov 22, 1960||Alexander Winterberg||Method of preserving perishable foodstuffs|
|US3205077 *||Aug 3, 1962||Sep 7, 1965||Nat Distillers Chem Corp||Coated polyolefin film and moisture emitting product enclosed therein|
|US3663240 *||Mar 24, 1969||May 16, 1972||Mayer & Co Inc O||Package and method of making same|
|US4058647 *||Feb 25, 1976||Nov 15, 1977||Mitsubishi Petrochemical Co., Ltd.||Process for preparing laminated resin product|
|US4276340 *||Jun 27, 1979||Jun 30, 1981||La Cellophane||Cellulose packaging films for packaging soft cheeses|
|US4292355 *||Jun 18, 1979||Sep 29, 1981||Composite Container Corporation||Moisture-impervious coextruded container|
|US4440824 *||Oct 4, 1982||Apr 3, 1984||Composite Container Corporation||Thermoformable coextruded multilayered structure|
|US4699846 *||Jun 27, 1984||Oct 13, 1987||Kureha Kagaku Kogyo Kabushiki Kaisha||Heat-resistant and oil-resistant laminate film and process for preparing the same|
|US4719153 *||Nov 12, 1985||Jan 12, 1988||Kuraray Co., Ltd.||Laminated article and process for production thereof|
|CA990228A *||Dec 23, 1971||Jun 1, 1976||Grace W R & Co||Packaging|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US5004647 *||May 27, 1988||Apr 2, 1991||W. R. Grace & Co.-Conn.||Oxygen barrier biaxially oriented film|
|US5158836 *||Feb 21, 1991||Oct 27, 1992||W. R. Grace & Co.-Conn.||Oriented film of high clarity and gloss|
|US5219002 *||Jan 17, 1991||Jun 15, 1993||Hoechst Aktiengesellschaft||Multilayered polyamide-based synthetic sausage casing|
|US5219666 *||Feb 26, 1992||Jun 15, 1993||W.R. Grace & Co.-Conn.||Oriented film of high clarity and gloss|
|US5296304 *||Feb 5, 1992||Mar 22, 1994||Mitsubishi Petrochemical Co., Ltd.||Laminate film for stretch-wrapping and process for producing the same|
|US5389448 *||Apr 2, 1993||Feb 14, 1995||W.R. Grace & Co.-Conn.||Blends of polypropylene and ethylene copolymer and films made from the blend|
|US5434010 *||May 12, 1993||Jul 18, 1995||Viskase Corporation||Heat shrinkable very low density polyethylene terpolymer film|
|US5491019 *||Mar 28, 1994||Feb 13, 1996||W. R. Grace & Co.-Conn.||Oxygen-permeable multilayer film|
|US5492705 *||Oct 19, 1994||Feb 20, 1996||Dowbrands L.P.||Vegetable containing storage bag and method for storing same|
|US5523136 *||Apr 30, 1993||Jun 4, 1996||Cypress Packaging||Packaging film, packages and methods for using them|
|US5532053 *||Mar 1, 1994||Jul 2, 1996||W. R. Grace & Co.-Conn.||High moisture transmission medical film|
|US5540989 *||Feb 14, 1995||Jul 30, 1996||Roehm Gmbh Chemische Fabrik||Multilayered heat-sealable plastic films|
|US5638660 *||Jun 2, 1995||Jun 17, 1997||W. R. Grace & Co.-Conn.||Packaging process using oxygen-permeable multilayer film|
|US5744205 *||Jun 7, 1995||Apr 28, 1998||Toyo Seikan Kaisha, Ltd.||Semi-sealed or sealed package for preserving produce composed of resin covered paper|
|US5753290 *||Aug 21, 1996||May 19, 1998||Globe Manufacturing Co.||Processed meat and poultry encased in natural rubber thread with low nitrosamine|
|US5783270 *||Jun 3, 1996||Jul 21, 1998||W. R. Grace & Co.-Conn.||Packaging film, packages and methods for using them|
|US5811142 *||Dec 13, 1996||Sep 22, 1998||Tenneo Packaging||Modified atmosphere package for cut of raw meat|
|US5820956 *||Jun 23, 1995||Oct 13, 1998||Mitsubishi Gas Chemical Company, Inc.||Multi-layer structural body|
|US5849127 *||Jun 2, 1995||Dec 15, 1998||W. R. Grace & Co.-Conn.||Process for making an oxygen permeable multilayer film|
|US5928560 *||May 14, 1997||Jul 27, 1999||Tenneco Packaging Inc.||Oxygen scavenger accelerator|
|US5948457 *||Jun 9, 1998||Sep 7, 1999||Tenneco Packaging Inc.||Modified atmosphere package|
|US6054153 *||Apr 3, 1998||Apr 25, 2000||Tenneco Packaging Inc.||Modified atmosphere package with accelerated reduction of oxygen level in meat compartment|
|US6060136 *||Jul 7, 1997||May 9, 2000||Cryovac, Inc.||High modulus oxygen-permeable multilayer film|
|US6100357 *||May 12, 1993||Aug 8, 2000||Viskase Corporation||Heat shrinkable very low density polyethylene terpolymer film|
|US6132781 *||Dec 17, 1999||Oct 17, 2000||Pactiv Corporation||Modified atmosphere package with accelerated reduction of oxygen level in meat compartment|
|US6183790||Aug 27, 1999||Feb 6, 2001||Pactiv Corporation||Modified atmosphere package|
|US6197909||May 12, 1993||Mar 6, 2001||Curwood, Inc.||Heat shrinkable C2C4C6 terpolymer film|
|US6231905||Oct 8, 1998||May 15, 2001||Delduca Gary R.||System and method of making a modified atmosphere package comprising an activated oxygen scavenger for packaging meat|
|US6294210||Sep 12, 1997||Sep 25, 2001||Cryovac, Inc.||Oxygen permeable multilayer film|
|US6296923 *||Jun 8, 1994||Oct 2, 2001||Sidlaw Flexible Packaging Limited||Perforated polymeric film with limited oxygen and water permeability|
|US6315921||Jul 2, 1999||Nov 13, 2001||Pactiv Corporation||Oxygen scavenger accelerator|
|US6321509||Jun 11, 1999||Nov 27, 2001||Pactiv Corporation||Method and apparatus for inserting an oxygen scavenger into a modified atmosphere package|
|US6395195||Jan 10, 2000||May 28, 2002||Pactiv Corporation||Oxygen scavenger accelerator|
|US6494023||Aug 10, 2001||Dec 17, 2002||Pactiv Corporation||Apparatus for inserting an oxygen scavenger into a modified atmosphere package|
|US6508955 *||Nov 12, 1999||Jan 21, 2003||Pactiv Corporation||Oxygen scavenger accelerator|
|US6517950||Aug 13, 1999||Feb 11, 2003||Cryovac, Inc.||High modulus oxygen-permeable multilayer film, packaging process using same, and packaged product comprising same|
|US6528173||Oct 23, 1998||Mar 4, 2003||Baxter International Inc.||Coextruded multilayer films for sterilizable fluid containers|
|US6589615||Jan 4, 1999||Jul 8, 2003||William W. Yen||Thermoplastic food casing|
|US6666988||Nov 4, 2002||Dec 23, 2003||Pactiv Corporation||Methods of using an oxygen scavenger|
|US6926846||Sep 30, 2003||Aug 9, 2005||Pactiv Corporation||Methods of using an oxygen scavenger|
|US7147799||Jun 13, 2005||Dec 12, 2006||Pactiv Corporation||Methods of using an oxygen scavenger|
|US7192636 *||Dec 9, 2003||Mar 20, 2007||Intertape Polymer Corp.||Multilayer shrink film with polystyrene and polyethylene layers|
|US7833594||Feb 3, 2003||Nov 16, 2010||Casematic, S.A. De C.V.||Polymer based sausage casing|
|US8835015 *||Dec 20, 2004||Sep 16, 2014||Toray Plastics (America), Inc.||High oxygen transmission biaxially oriented film with improved tensile properties|
|US20030054073 *||Jul 3, 2002||Mar 20, 2003||Delduca Gary R.||Modified atmosphere packages and methods for making the same|
|US20030207000 *||Apr 25, 2003||Nov 6, 2003||Merriman Marcus C.||Modified atmosphere packages and methods for making the same|
|US20040062834 *||Sep 26, 2002||Apr 1, 2004||Casematic, S.A. De C.V.||Polyamide-based sausage casing|
|US20040062888 *||Feb 3, 2003||Apr 1, 2004||Casematic, S.A. De C.V.||Polymer-based sausage casing|
|US20040166348 *||Dec 9, 2003||Aug 26, 2004||Shane Taghavi||Multilayer shrink film with polystyrene and polyethylene layers|
|US20040219198 *||Apr 14, 2004||Nov 4, 2004||3M Innovative Properties Company||Transdermal drug delivery device with multilayer backing|
|US20050058754 *||Oct 21, 2004||Mar 17, 2005||Delduca Gary R.||Modified atmospheric package|
|US20050129969 *||Dec 16, 2003||Jun 16, 2005||Schell Thomas A.||Heat-shrinkable packaging films with improved sealing properties and articles made thereof|
|US20050142372 *||Dec 20, 2004||Jun 30, 2005||Toray Plastics (America), Inc.||High oxygen transmission biaxially oriented film with improved tensile properties|
|US20050208184 *||Oct 21, 2004||Sep 22, 2005||Delduca Gary R||Method of forming a modified atmospheric package|
|US20060233987 *||Apr 19, 2005||Oct 19, 2006||Cryovac, Inc.||Laminate having a high oxygen transmission rate|
|US20070092610 *||Oct 21, 2005||Apr 26, 2007||Cryovac, Inc.||Multicomponent package|
|US20070275196 *||May 25, 2006||Nov 29, 2007||Cryovac, Inc.||Multilayer Film Having High Oxygen Transmission and High Modulus|
|US20100272975 *||Apr 23, 2009||Oct 28, 2010||Chevron Phillips Chemical Company Lp||System and method for the production and use of lamination films|
|WO2004052636A2 *||Dec 10, 2003||Jun 24, 2004||Ipg Technologies, Inc.||Multilayer shrink film with polystyrene and plyethylene layers|
|WO2004052636A3 *||Dec 10, 2003||Dec 29, 2004||Ipg Technologies Inc||Multilayer shrink film with polystyrene and plyethylene layers|
|WO2009011914A3 *||Jul 18, 2008||Mar 12, 2009||Josh Buesseler||Sealable closure systems and parts thereof|
|U.S. Classification||426/127, 428/518, 428/34.8, 426/130, 428/517, 426/415, 428/516|
|International Classification||B32B27/08, B65D65/40, B32B7/02, B32B27/28, B65D85/76, B32B25/16|
|Cooperative Classification||Y10T428/3192, Y10T428/31917, Y10T428/31913, B32B7/02, B65D85/76, B32B27/28, Y10T428/1324, B32B27/08|
|European Classification||B32B27/28, B32B7/02, B32B27/08, B65D85/76|
|Jul 13, 1987||AS||Assignment|
Owner name: W.R. GRACE & CO., DUNCAN, SOUTH CAROLINA, (P.O. BO
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:CANDIDA, GIOVANNI;PERAZZO, LUIGI;REEL/FRAME:004755/0822
Effective date: 19870526
|Sep 5, 1989||AS||Assignment|
Owner name: W.R. GRACE & CO.-CONN, A CORP. OF CT
Free format text: MERGER;ASSIGNORS:W.R. GRACE & CO.;GRACE MERGER CORPORATION;REEL/FRAME:005169/0141
Effective date: 19880525
|Jul 16, 1993||FPAY||Fee payment|
Year of fee payment: 4
|Jul 17, 1997||FPAY||Fee payment|
Year of fee payment: 8
|Aug 17, 1998||AS||Assignment|
Owner name: CRYOVAC, INC., SOUTH CAROLINA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:W.R. GRACE & CO.-CONN.;REEL/FRAME:009405/0001
Effective date: 19980814
|Jul 12, 2001||FPAY||Fee payment|
Year of fee payment: 12